Game development is really interesting work, actually when you look at a computer game and the AI implemented in it and its graphics and complexity, you then feel it is impossible to build such type of games. But if you know that all these games are depending on graphics libraries which made developing games very easy task, you will be interested in designing and developing games. We are going to prove that here by developing a simple 2D game depending on OpenGL library, we will introduce the concept of scene rendering and object collision, and also we will show how to write a text on the screen to get the score of the player. Finally we will show how to use the keyboard and mouse to interact with the game.
The game basics:
When you develop a game you have to fully understand how the game is played, so you can implement its logic. Our game is a simple ball with bat game. The bat will be moved according to the movement of the mouse. And the ball will move randomly in the created window. When the ball hits the right, left, or top wall – we will refer to the window border as a wall – it will return back. When it hits the bottom wall it will not only return back but it will increase the score of the computer, but if the player can hold it by the bat, his score will be increased. Let us take a look at the interface of the game. The interface of the game is depicted in Fig. 1.
The window contains two counters, the first is PC: it is for the computer, it increases only if the ball hits the bottom border of the window (bottom wall). Player: it is a counter increases only if the ball hits your bat (the bat is represented by the rectangle at the bottom of the screen).
This tutorial takes a look at using UMG to create a simple 2D UI for your game and demonstrates the code required to display the UI. This tutorial looks at playing Audio in Unreal Engine 4, both using PlaySound 2D, at a location or as a component. Also covers importing audio and creating more complex mixed audio. Related Articles. Ruby’s Adventure is a project that will guide beginner creators into 2D game development and coding. Ruby’s journey will teach you how – and why – to use sprites, how to create your first script, use the Tilemap tool, decorate your scene, and create particles, user interface (UI), audio and more. Learn C game development is a course I made for everyone who knows how to program, but doesn't know where to start with game development. The course teaches you how to use the SFML library for C, to start working with graphics, events and sound to create a 2D game.
The game implementation
Please help me in this. I am using dev c. You have to make a racing game in C. There are two players in your program. They play by throwing 3 dices and then moving forward. Your program should start and ask you to press any key for a toss. After a fair toss, one of the players i.e. Player 1 or player 2 starts the game. But it was worth it. Now, I realize game development is like any skill — you only get better by doing, failing, then improving. I taught myself everything I know. And now I’m going to teach you. To make a game, you must go through the 6 stages of game development: Design. A good beginner-friendly game engine won't overwhelm with options at first glance. It should have an easy-to-use interface and a straightforward way of creating logic. Also important are strong learning resources (examples, tutorials and good documentation) and an active community that can help out when stuck. 2D games Charles Kelly Programming 2D g ames Computer Game Programming K14701 Most of today’s commercial games are written in C and are created using a game engine. Addressing both of these key elements, Programming 2D Games provides a complete, up-to-date introduction to game programming. All of the code in the book was carefully crafted.
We will show step by step how to implement the game. First of all the concept of motion in OpenGL should be clear, the motion is done by drawing and looping. In every loop, the position of the object is adjusted so you fell it is moving. Motion in OpenGL has the same concept as the Cartoon films, every cycle the drawing is adjusted little bit and then all the images are displayed together which results in “moving” characters.
Drawing the window
The window in OpenGL is implemented simply by the following code segment
First, the window initialization is done, and the color mode is set to RGB. Then a size of the window is defined as 795 for width and 500 for the height. Then the position of the window will be at 0,0 which is in the upper left corner of the computer screen. Finally a title is assigned to the window; this title will appear in the title bar or our window.
Drawing the Ball and the Bat and Displaying the Score Text
As we said the ball will be represented by a rectangle. For that we will define a new structure called RECTA, which is implemented by defining the left, top, right, and bottom coordinates. We are going to define three variables of this structure to be used as Ball, Wall, and Bat respectively
Then we will use the DrawRectangle function to draw the RECTA instances on OpenGL window.
The rectangle is drawn in OpenGL by using its corners coordinates. We start by the left-bottom corner and rotating counter-clockwise. glBegin(GL_QUADS) and glEnd() functions will encapsulate the rectangle coordinates. For the text, we need to write two words PC: (the score of the computer) Player: (The score of the player or the user). To do that we have implemented a function called drawText, it is shown in the following code segment
The function draws a string of type char* at position x,y. First we need to Push the matrix into the stack – so the next functions will not be affected by previous processing – then we translate the OpenGL cursor to position x, y then we scale the text to control its size (you are free to play with the values in glScalef function and see the effect of each value). Then we loop through the string (char* array) and draw every character separately by using the function glutStrokeCharacter. GLUT_STROKE_ROMAN is the name of the used font. Finally we pop the matrix from the stack so the previous settings are returned back.
Moving the Ball and the Bat
As we said before, the motion of the Ball (the square) is done by adjusting the square position in each loop. The Ball has a speed (this will be defined by a Timer Function together with the length of the Ball movement steps- in our program we call this steps “delta”). For the timer function it always contains a code that will be executed in a regular basis every specified period of time (every 1 millisecond in our program). Our timer function is depicted in the following code segment
We have defined two global variables Xspeed and Yspeed, which has the value of delta=1. This can be shown graphically in Fig. 2. The value of delta will be changed (+1/-1) according to the collision of the ball with the walls. If the ball hits the right wall Xspeed will be –delta (this will make the ball return back), if the ball hits the left wall the Xspeed will be changed to delta and so on. For Yspeed also if the ball hits the top wall it will be equal delta, however if it hits the bottom wall or the bat, it will be –delta. The most important point here is that the Xspeed, Yspead will be used to increase the position of the ball, which was clearly done in the Timer function (refer to the above code segment). For changing the values of Xspeed and Yspeed, it is shown in the following code segment
CThreeMaxLoader contains the following function which responsible for loading the 3DS file:
In the above code segment, the variable pcResult holds the counter of the computer score. Also we noticed the existence of a new function called Test_Ball_Wall(ball,wall). This function is used to detect the collision between the ball and the walls. The collision detection will be explained in the next section.
Moving the bat will be done by moving the mouse cursor, when the mouse cursor is moved, only the x coordinate of the bat will be changed, the movement of the bat is shown in the following code segment
We have defined a global variable called mouse_x. it will be used in drawing the bat when we render the whole scene. You can stop the game by pressing the Esc. key from the keyboard this is programmed as follow
Ball collision detection
As we described in the previous section, when the ball hits the wall it will reflect back. The detection of the collision between the ball and wall (taking an example the right wall) is done simply by comparing the right coordinate of the wall with the ball’s right coordinate, the collision will occur if they are the same or the ball’s right is greater. For the bat/ball collision is done by comparing the top of the bat with the bottom of the ball. A collision occurs if they are the same or the balls bottom is greater and the x-coordinate lie inside the bat’s x coordinates. The following code shows the above procedure
As we can expect playerResult is a global variable holds the score of the player.
Putting all things together
We are going to show how the above code will be used in rendering the whole scene of the game. First take a look at the Render function
As we mentioned before the Render function will run every OpenGL loop. So, first we need to clear and load the identity matrix to the window, and then we will use the drawText function to draw the text for the PC and Player scores. Then we define the walls coordinates (it will have the same size as the created OpenGL window) and then draw the ball. Then we detect the collision between the ball and the wall and between the ball and the bat, and accordingly increase the scores of the PC and the player. Finally we move the player according to the movement of the mouse.
The Game’s Source Code
To download a sample code of the above tutorial click here. You need to install Visual C++ 6 and Install the OpenGL and GLUT libraries to be able to run the source code.
Lately I’ve been writing a game engine in C++. I’m using it to make a little mobile game called Hop Out. Here’s a clip captured from my iPhone 6. (Unmute for sound!)
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Hop Out is the kind of game I want to play: Retro arcade gameplay with a 3D cartoon look. The goal is to change the color of every pad, like in Q*Bert.
Hop Out is still in development, but the engine powering it is starting to become quite mature, so I thought I’d share a few tips about engine development here.
Why would you want to write a game engine? There are many possible reasons:
- You’re a tinkerer. You love building systems from the ground up and seeing them come to life.
- You want to learn more about game development. I spent 14 years in the game industry and I’m still figuring it out. I wasn’t even sure I could write an engine from scratch, since it’s vastly different from the daily responsibilities of a programming job at a big studio. I wanted to find out.
- You like control. It’s satisfying to organize the code exactly the way you want, knowing where everything is at all times.
- You feel inspired by classic game engines like AGI (1984), id Tech 1 (1993), Build (1995), and industry giants like Unity and Unreal.
- You believe that we, the game industry, should try to demystify the engine development process. It’s not like we’ve mastered the art of making games. Far from it! The more we examine this process, the greater our chances of improving upon it.
The gaming platforms of 2017 – mobile, console and PC – are very powerful and, in many ways, quite similar to one another. Game engine development is not so much about struggling with weak and exotic hardware, as it was in the past. In my opinion, it’s more about struggling with complexity of your own making. It’s easy to create a monster! That’s why the advice in this post centers around keeping things manageable. I’ve organized it into three sections:
- Use an iterative approach
- Think twice before unifying things too much
- Be aware that serialization is a big subject
This advice applies to any kind of game engine. I’m not going to tell you how to write a shader, what an octree is, or how to add physics. Those are the kinds of things that, I assume, you already know that you should know – and it depends largely on the type of game you want to make. Instead, I’ve deliberately chosen points that don’t seem to be widely acknowledged or talked about – these are the kinds of points I find most interesting when trying to demystify a subject.
Use an Iterative Approach
My first piece of advice is to get something (anything!) running quickly, then iterate.
If possible, start with a sample application that initializes the device and draws something on the screen. In my case, I downloaded SDL, opened Xcode-iOS/Test/TestiPhoneOS.xcodeproj
, then ran the testgles2
sample on my iPhone.
Voilà! I had a lovely spinning cube using OpenGL ES 2.0.
My next step was to download a 3D model somebody made of Mario. I wrote a quick & dirty OBJ file loader – the file format is not that complicated – and hacked the sample application to render Mario instead of a cube. I also integrated SDL_Image to help load textures.
Then I implemented dual-stick controls to move Mario around. (In the beginning, I was contemplating making a dual-stick shooter. Not with Mario, though.)
Next, I wanted to explore skeletal animation, so I opened Blender, modeled a tentacle, and rigged it with a two-bone skeleton that wiggled back and forth.
At this point, I abandoned the OBJ file format and wrote a Python script to export custom JSON files from Blender. These JSON files described the skinned mesh, skeleton and animation data. I loaded these files into the game with the help of a C++ JSON library.
Once that worked, I went back into Blender and made more elaborate character. (This was the first rigged 3D human I ever created. I was quite proud of him.)
Over the next few months, I took the following steps:
- Started factoring out vector and matrix functions into my own 3D math library.
- Replaced the
.xcodeproj
with a CMake project. - Got the engine running on both Windows and iOS, because I like working in Visual Studio.
- Started moving code into separate “engine” and “game” libraries. Over time, I split those into even more granular libraries.
- Wrote a separate application to convert my JSON files into binary data that the game can load directly.
- Eventually removed all SDL libraries from the iOS build. (The Windows build still uses SDL.)
The point is: I didn’t plan the engine architecture before I started programming. This was a deliberate choice. Instead, I just wrote the simplest code that implemented the next feature, then I’d look at the code to see what kind of architecture emerged naturally. By “engine architecture”, I mean the set of modules that make up the game engine, the dependencies between those modules, and the API for interacting with each module.
This is an iterative approach because it focuses on smaller deliverables. It works well when writing a game engine because, at each step along the way, you have a running program. If something goes wrong when you’re factoring code into a new module, you can always compare your changes with the code that worked previously. Obviously, I assume you’re using some kind of source control.
You might think a lot of time gets wasted in this approach, since you’re always writing bad code that needs to be cleaned up later. But most of the cleanup involves moving code from one .cpp
file to another, extracting function declarations into .h
files, or equally straightforward changes. Deciding where things should go is the hard part, and that’s easier to do when the code already exists.
I would argue that more time is wasted in the opposite approach: Trying too hard to come up with an architecture that will do everything you think you’ll need ahead of time. Two of my favorite articles about the perils of over-engineering are The Vicious Circle of Generalization by Tomasz Dąbrowski and Don’t Let Architecture Astronauts Scare You by Joel Spolsky.
I’m not saying you should never solve a problem on paper before tackling it in code. I’m also not saying you shouldn’t decide what features you want in advance. For example, I knew from the beginning that I wanted my engine to load all assets in a background thread. I just didn’t try to design or implement that feature until my engine actually loaded some assets first.
The iterative approach has given me a much more elegant architecture than I ever could have dreamed up by staring at a blank sheet of paper. The iOS build of my engine is now 100% original code including a custom math library, container templates, reflection/serialization system, rendering framework, physics and audio mixer. I had reasons for writing each of those modules, but you might not find it necessary to write all those things yourself. There are lots of great, permissively-licensed open source libraries that you might find appropriate for your engine instead. GLM, Bullet Physics and the STB headers are just a few interesting examples.
Think Twice Before Unifying Things Too Much
As programmers, we try to avoid code duplication, and we like it when our code follows a uniform style. However, I think it’s good not to let those instincts override every decision.
Resist the DRY Principle Once in a While
To give you an example, my engine contains several “smart pointer” template classes, similar in spirit to std::shared_ptr
. Each one helps prevent memory leaks by serving as a wrapper around a raw pointer.
Owned<>
is for dynamically allocated objects that have a single owner.Reference<>
uses reference counting to allow an object to have several owners.audio::AppOwned<>
is used by code outside the audio mixer. It allows game systems to own objects that the audio mixer uses, such as a voice that’s currently playing.audio::AudioHandle<>
uses a reference counting system internal to the audio mixer.
It may look like some of those classes duplicate the functionality of the others, in violation of the DRY (Don’t Repeat Yourself) Principle. Indeed, earlier in development, I tried to re-use the existing Reference<>
class as much as possible. However, I found that the lifetime of an audio object is governed by special rules: If an audio voice has finished playing a sample, and the game does not hold a pointer to that voice, the voice can be queued for deletion immediately. If the game holds a pointer, then the voice object should not be deleted. And if the game holds a pointer, but the pointer’s owner is destroyed before the voice has ended, the voice should be canceled. Rather than adding complexity to Reference<>
, I decided it was more practical to introduce separate template classes instead.
95% of the time, re-using existing code is the way to go. But if you start to feel paralyzed, or find yourself adding complexity to something that was once simple, ask yourself if something in the codebase should actually be two things.
It’s OK to Use Different Calling Conventions
One thing I dislike about Java is that it forces you to define every function inside a class. That’s nonsense, in my opinion. It might make your code look more consistent, but it also encourages over-engineering and doesn’t lend itself well to the iterative approach I described earlier.
In my C++ engine, some functions belong to classes and some don’t. For example, every enemy in the game is a class, and most of the enemy’s behavior is implemented inside that class, as you’d probably expect. On the other hand, sphere casts in my engine are performed by calling sphereCast()
, a function in the physics
namespace. sphereCast()
doesn’t belong to any class – it’s just part of the physics
module. I have a build system that manages dependencies between modules, which keeps the code organized well enough for me. Wrapping this function inside an arbitrary class won’t improve the code organization in any meaningful way.
Then there’s dynamic dispatch, which is a form of polymorphism. We often need to call a function for an object without knowing the exact type of that object. A C++ programmer’s first instinct is to define an abstract base class with virtual functions, then override those functions in a derived class. That’s valid, but it’s only one technique. There are other dynamic dispatch techniques that don’t introduce as much extra code, or that bring other benefits:
- C++11 introduced
std::function
, which is a convenient way to store callback functions. It’s also possible to write your own version ofstd::function
that’s less painful to step into in the debugger. - Many callback functions can be implemented with a pair of pointers: A function pointer and an opaque argument. It just requires an explicit cast inside the callback function. You see this a lot in pure C libraries.
- Sometimes, the underlying type is actually known at compile time, and you can bind the function call without any additional runtime overhead. Turf, a library that I use in my game engine, relies on this technique a lot. See
turf::Mutex
for example. It’s just atypedef
over a platform-specific class. - Sometimes, the most straightforward approach is to build and maintain a table of raw function pointers yourself. I used this approach in my audio mixer and serialization system. The Python interpreter also makes heavy use of this technique, as mentioned below.
- You can even store function pointers in a hash table, using the function names as keys. I use this technique to dispatch input events, such as multitouch events. It’s part of a strategy to record game inputs and play them back with a replay system.
Dynamic dispatch is a big subject. I’m only scratching the surface to show that there many ways to achieve it. The more you write extendible low-level code – which is common in a game engine – the more you’ll find yourself exploring alternatives. If you’re not used to this kind of programming, the Python interpreter, which is written an C, is an excellent resource to learn from. It implements a powerful object model: Every PyObject
points to a PyTypeObject
, and every PyTypeObject
contains a table of function pointers for dynamic dispatch. The document Defining New Types is a good starting point if you want to jump straight right in.
Be Aware that Serialization Is a Big Subject
Serialization is the act of converting runtime objects to and from a sequence of bytes. In other words, saving and loading data.
For many if not most game engines, game content is created in various editable formats such as .png
, .json
, .blend
or proprietary formats, then eventually converted to platform-specific game formats that the engine can load quickly. The last application in this pipeline is often referred to as a “cooker”. The cooker might be integrated into another tool, or even distributed across several machines. Usually, the cooker and a number of tools are developed and maintained in tandem with the game engine itself.
When setting up such a pipeline, the choice of file format at each stage is up to you. You might define some file formats of your own, and those formats might evolve as you add engine features. As they evolve, you might find it necessary to keep certain programs compatible with previously saved files. No matter what format, you’ll ultimately need to serialize it in C++.
There are countless ways to implement serialization in C++. One fairly obvious way is to add load
and save
functions to the C++ classes you want to serialize. You can achieve backward compatibility by storing a version number in the file header, then passing this number into every load
function. This works, although the code can become cumbersome to maintain.
It’s possible to write more flexible, less error-prone serialization code by taking advantage of reflection – specifically, by creating runtime data that describes the layout of your C++ types. For a quick idea of how reflection can help with serialization, take a look at how Blender, an open source project, does it.
When you build Blender from source code, many steps happen. First, a custom utility named makesdna
is compiled and run. This utility parses a set of C header files in the Blender source tree, then outputs a compact summary of all C types defined within, in a custom format known as SDNA. This SDNA data serves as reflection data. The SDNA is then linked into Blender itself, and saved with every .blend
file that Blender writes. From that point on, whenever Blender loads a .blend
file, it compares the .blend
file’s SDNA with the SDNA linked into the current version at runtime, and uses generic serialization code to handle any differences. This strategy gives Blender an impressive degree of backward and forward compatibility. You can still load 1.0 files in the latest version of Blender, and new .blend
files can be loaded in older versions.
Like Blender, many game engines – and their associated tools – generate and use their own reflection data. There are many ways to do it: You can parse your own C/C++ source code to extract type information, as Blender does. You can create a separate data description language, and write a tool to generate C++ type definitions and reflection data from this language. You can use preprocessor macros and C++ templates to generate reflection data at runtime. And once you have reflection data available, there are countless ways to write a generic serializer on top of it.
How To Make A 2d Game In Dev C 2b 2b 3
Clearly, I’m omitting a lot of detail. In this post, I only want to show that there are many different ways to serialize data, some of which are very complex. Programmers just don’t discuss serialization as much as other engine systems, even though most other systems rely on it. For example, out of the 96 programming talks given at GDC 2017, I counted 31 talks about graphics, 11 about online, 10 about tools, 4 about AI, 3 about physics, 2 about audio – but only one that touched directly on serialization.
At a minimum, try to have an idea how complex your needs will be. If you’re making a tiny game like Flappy Bird, with only a few assets, you probably don’t need to think too hard about serialization. You can probably load textures directly from PNG and it’ll be fine. If you need a compact binary format with backward compatibility, but don’t want to develop your own, take a look at third-party libraries such as Cereal or Boost.Serialization. I don’t think Google Protocol Buffers are ideal for serializing game assets, but they’re worth studying nonetheless.
Writing a game engine – even a small one – is a big undertaking. There’s a lot more I could say about it, but for a post of this length, that’s honestly the most helpful advice I can think to give: Work iteratively, resist the urge to unify code a little bit, and know that serialization is a big subject so you can choose an appropriate strategy. In my experience, each of those things can become a stumbling block if ignored.
How To Make A 2d Game In Dev C 2b 2b 1b
I love comparing notes on this stuff, so I’d be really interested to hear from other developers. If you’ve written an engine, did your experience lead you to any of the same conclusions? And if you haven’t written one, or are just thinking about it, I’m interested in your thoughts too. What do you consider a good resource to learn from? What parts still seem mysterious to you? Feel free to leave a comment below or hit me up on Twitter!
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